Microalgae – under the microscope

[New Zealand] Microalgae are one of the world’s tiniest life forms, but they can pack a powerful punch. They’re not known as ‘killer algae’ for nothing.

Around the world, toxic algal blooms wreak havoc on fishing and marine life. Here in New Zealand, such blooms have led to the temporary shutdown of shellfish harvesting in some areas and short-term closures at some of our swimming beaches. And at our lakes and rivers, toxic blue-green algae has killed more than 50 dogs over the past decade.

Scientists around the world, have been trying to gain a better understanding of these toxic algae to help in monitoring and managing their effects. Key to that research in New Zealand is a nationally significant collection of microalgae cultures known as the Cawthron Institute Culture Collection of Microalgae (CICCM).

Flasks holding specimen from the microalgae culture collection

The CICCM was recently moved into a new home in Cawthron Institute’s recently built Envirotech building in central Nelson. The laboratory includes cabinets that are purpose-built to hold the tropical collection and LED lighting to create optimum growing conditions for the collection’s microalgae.

Cawthron research scientist Dr Lesley Rhodes says the CICCM is essential to the government-funded Safe New Zealand Seafood Programme which is led by Cawthron Institute in partnership with AgResearch, Plant & Food Research, and the Institute of Environmental Science and Research (ESR).

“The programme provides research that safeguards and promotes the safe reputation of New Zealand seafood and the collection provides the producers of the toxins being studied or produced as chemical standards for monitoring,” she says.

In its 21st year, the Safe New Zealand Seafood Programme and the CICCM have grown up together. “Initially, individual scientists maintained cultures of species they were working with, but that was impractical on many levels and it also meant that cultures couldn’t be easily shared. It became apparent that we needed a central repository for all of the microalgae we were working with,” Dr Rhodes says.

From just a handful of microalgae, the CICCM now houses about 300 cryopreserved strains of toxic microalgae and cyanobacteria, along with a living collection of another nearly 300 microalgae that includes representatives from most of the world’s toxic algae species. Of national and international significance, the collection is part of the Asia Oceania Algae Culture Collection network.

“The programme provides research that safeguards and promotes the safe reputation of New Zealand seafood and the collection provides the producers of the toxins being studied or produced as chemical standards for monitoring,” Dr Rhodes says.

Beyond the Safe New Zealand Seafood Programme, because the CICCM contains some of the worst “nasties” known to exist in our marine and fresh water environment, samples are in constant demand by researchers around the world, including the United States, Australia, China, Japan, and the United Kingdom.

“The samples have led to a greater understanding of toxic microalgae and that is already having huge implications for industries like aquaculture,” says Dr Rhodes. “For example, the collection has assisted researchers in improving the New Zealand mussel industry’s monitoring programmes which has allowed for more geographically targeted temporary closures and has meant savings for the industry.”

The collection also includes microalgae with the capability to produce valuable compounds – some of which have only been found in New Zealand waters. The compounds are being investigated for their use in products ranging from pharmaceuticals to renewable energy sources.

A living collection

The collection includes microalgae that need to be regularly transferred into fresh nutrient-based media. In fact, in some ways the living part of the collection is more like a microalgae crèche.

Krystyna Ponikla has spent the last 16 years as the collection’s curator and has become an expert on the needs of each microalgae species. “Just like other living organisms, each group of microalgae have specific nutritional requirements. We prepare special meals or a ‘medium’ that includes the right vitamins, trace metals, and other essential nutrients for each of those groups.”

She says that new strains of microalgae are regularly deposited to the collection. Her time is also spent checking the microalgae under the microscope. “That’s how we check the health of the microalgae – we look at individual cells for signs that they are thriving and reproducing.”

Krystyna Ponikla and Sarah Challenger in the new culture collection room.Beyond maintaining the collection, she keeps meticulous records with every strain having its own ‘identification certificate’. “For researchers it’s absolutely critical that they know where the sample was collected, along with identification records and how long and under what conditions it has been kept.”Currently Sarah Challenger has been training as a new curator, part of a succession plan for the collection.

The search for harmful algae

As part of a robust monitoring system, the CICCM is used to train laboratory staff in identifying algae in routine water samples, giving the Ministry for Primary Industries, public health officials and others the tools they need to identify harmful algal blooms. This training also includes identifying fresh water bodies that may be contaminated by cyanobacteria. Cyanobacteria are widespread in New Zealand with some species producing natural toxins that can cause illness or even death to people and animals if they are ingested.

Phormidium spp. – mat-forming toxic cyanobacteria – grow on river beds and have been identified as the cause of many dog deaths around New Zealand

In 2014, Cawthron hosted an international conference on harmful algae. The conference allowed scientists from around the world to present their research and interact with regulators and industry representatives to explore ways in which science can be applied to meet the challenges of the future.

The people behind the science

Names: Lesley Rhodes and Kirsty Smith

Title: Research Scientists, Co-Leaders of Cawthron’s Culture Collection of Microalgae

Lesley also co-leads the Safe New Zealand Seafood Programme with Tim Harwood, a research chemist at Cawthron.

Field of study: Marine toxic algal blooms

Favourite part of the work: “This is one of those great jobs where we frequently make new discoveries that have implications for the well-being of New Zealanders, along with our environment and economy. It’s incredibly rewarding work.”

What Lesley’s most proud of: “One of the highlights of my career has been Cawthron’s contributions to the discovery of the producer of pinnatoxins, the dinoflagellate Vulcanodinium rugosum. The discovery was crucial from a public health perspective and to the local community and the aquaculture industry as the pinnatoxins in oysters had led to a shellfish harvesting closure at Rangaunu Harbour, Northland for many years. The CICCM now holds many isolates of the dinoflagellate, from as far afield as Australasia, the Americas, and Asia, and the research has expanded to include toxicology and pharmacology. Recently Kirsty and I found 2 new Gambierdiscus species in the Cook Islands. Gambierdiscus is the genus responsible for ciguatera fish poisoning throughout the Pacific.”

A special priority would be given to any locations that are subject to a "state of emergency" designation within the previous 12 months because of blooms. In Florida, 13 counties affected by algal blooms this summer fall under that designation.

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